Auditing of wireless network node databases

ABSTRACT

Synchronizing database files of a central node with database files of a local node in which the central node is coupled to the local node via a communication link. The communication link performance being continuously monitored via a periodic signal sent back and forth between the central node and local node. Information indicative of the files of the central database are integrated with the monitoring signal portion sent from the central node to the local node and a determination is made whether the files integrated with the monitoring signal corresponds with files of the local database via indications in the monitoring signal portion returned from the local node.

This application is a continuation of U.S. patent application Ser. No.10/910,381, filed Aug. 3, 2004, now U.S. Pat. No. 7,627,328, the contentof which is incorporated by reference herein in its entirety.

TECHNICAL FIELD OF THE INVENTION

The invention relates generally to telecommunications and, moreparticularly to auditing of node databases in a wirelesstelecommunication network.

BACKGROUND OF THE INVENTION

The popularity of wireless telephony has grown at an exponential rateover the past several years. As an increasing number of people usewireless telephones as a substitute for traditional wireline telephones,telecommunications service providers must be ready to seamlessly provideservice features and facilities normally associated with wirelineservice to the users of wireless telephony services.

One important and government mandated service required in both wirelineand wireless telephony is public safety administration services (alsoknown as emergency or “911” services). The hallmark of 911 service isthe ability of the emergency service personnel to view the address of adistressed caller while the call is ongoing. In wireline applications,911 service is easily administered because the caller uses equipmentassociated with a fixed address or location. Indeed, the caller'saddress aids 911 personnel in identifying appropriate emergency servicesunits to respond to the distressed caller's request. In resolving anemergency, the position information may be used by the emergencyservices network in a variety of ways. For example, it may be used toplot a point on a map, to provide the nearest known street address, oran input to navigation equipment in the emergency response vehicle.

Wireless telephony poses an entirely new challenge for emergency serviceadministration. Due to the very nature of wireless telephony, adistressed caller may be using a mobile unit in any geographic regionwhere wireless service is provided. The challenge for emergencypersonnel and wireless service providers is to pinpoint the location ofa distressed caller so that appropriate emergency service personnel maybe dispatched.

The Federal Communication Commission (FCC) has mandated that wirelesstelecommunication service providers include the capability to locate amobile subscriber unit within a certain geographical area. Severaltechnologies have emerged and are being developed to meet the governmentmandate, including, navigational systems such as the global positioningsystem GPS, wireless assisted GPS, angle of arrival, time difference ofarrival, RF fingerprinting and enhanced forward link triangulation.These technologies offer various degrees of accuracy and technologicalsuperiority in locating a mobile subscriber unit. Concurrent with theemergence of these position determination technologies, severalstandards have emerged and are being developed for obtaining locationinformation.

Position information may be delivered to the emergency services networkin two basic ways: with the call as part of the call setup informationor through a separate data service. The former is known as CallAssociated Signaling (CAS) since the position information is deliveredin the call signaling. The latter is NCAS and the messages delivered bythe data service must be correlated with the call by parameters carriedin the message. With NCAS, an Emergency Services Message Entity pullsthe position information from the wireless network. Thus, the wirelessnetwork uses the above-mentioned positioning technologies to position amobile subscriber unit.

The American National Standards Institute wireless standards committee(ANSI-41) examining the issues and technologies for meeting the FCCmandate (i.e., the wireless carrier must provide the coordinates of themobile unit's position to a emergency call center) concluded that thebasic functionality necessary for implementation should use non-callpath associated signaling (NCAS) in order to meet the situationalcontingencies and be implemented in the intelligent network on a servicecontrol point.

The Telecommunication Industry Association (TIA) Ad Hoc EmergencyServices (AHES) committee developed a standard, which would eventuallybecome a joint standard for ANSI-41 and GSM deployments of wirelessemergency services—the J-STD-036. The standard develops a referencenetwork model to describe the functional partitioning in which thefunctions are divided among several functional entities or nodes basedon traditional functional separations.

Many of these network nodes maintain databases for storing/correlatingfiles identifying system resources needed for enabling mobile unitpositioning. System resources can include mobile serving areas,controllers, and positioning equipment, for example. Successfulcommunication between network nodes depends on accurate synchronizationof files contained in the respective databases. This is particularlyimportant in an emergency service networks. Therefore, a need exists fora method and system for auditing network node databases to effectaccurate file synchronization.

SUMMARY OF THE INVENTION

Briefly described, in a first preferred form the present inventioncomprises a method for synchronizing database files of a central nodewith database files of a local node in which the central node is coupledto the local node via a communication link. The communication linkperformance being continuously monitored via a periodic signal sent backand forth between the central node and local node. A determination ismade whether the files of each database are synchronized by passinginformation in the monitoring signal.

Moreover, information indicative of the central database files areintegrated with the monitoring signal sent from the central node to thelocal node and a determination is made whether the files correspond withfiles of the local database via indications in the correspondingmonitoring signal returned from the local node. The communication linkcan be a conventional IP link and the monitoring signal can be aconventional heartbeat signal.

Moreover, each database file is sequentially included in successiveheartbeats of the monitoring signal such that each heartbeat includesinformation representing a different database file. Preferably, thecentral node is a Mobile Positioning Center (MPC) and the local node isa Position Determining Equipment (PDE) in a wireless emergency servicesnetwork which includes a plurality of Mobile Switching Centers (MSC) anda plurality of Cells associated therewith and each database file is anidentifier corresponding to a unique MSC and Cell combination. Moreover,one way of carrying out the invention is to include a mobile unitgeographical position request corresponding to a MPC database file in aheartbeat signal and then determining whether the returned heartbeatsignal received from the PDE indicates an error with the positionrequest. An error in the position request can be assumed to indicatethat the MPC file did not match a file in the PDE database. In addition,a report can be generated listing any MPC file which corresponds to aposition request indicated with an error.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a network representing a conventional ANSI-41 referencemodel for “network based” emergency call support services in accordancewith the J-STD-036 standard.

FIG. 2 shows a conventional database arrangement for network nodes.

FIG. 3 shows a flow diagram illustrating a conventional heartbeatcommunication scheme.

FIG. 4 shows a flow diagram illustrating an audit method in accordancewith exemplary embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to systems for auditing node databasesin a wireless telecommunication network in which the audits are in realtime or near real time. “Wireless” refers to cellular, PersonalCommunication Services, and other commercial mobile radio services anddoes not apply to cordless telephones or private radio systems. Methodsand systems envisioned by the present invention minimize errorspropagated in emergency caller location inquires due to databasesynchronization deficiencies.

Referring now to FIG. 1, there is shown a network representing asimplified version of the ANSI-41 reference model 100 for “networkbased” emergency call support services in accordance with the J-STD-036standard. “Network based” is a category of mobile positioning technologyknown in the wireless industry in which a conventional mobile network,in conjunction with network-based position equipment, is used toestimate the geographical position of a mobile station. The referencemodel 100 was developed to describe the functional partitioning in whichthe functions are divided among several functional entities or nodesbased on traditional functional separations.

Although aspects of the present invention are directed at network nodesof the mobile network portion 110, a general understanding of the entirereference model 100 is helpful for a better understanding. The referencemodel 100 includes a mobile network portion 110, a public safetyanswering point (PSAP) 130 and an emergency services network portion120.

The emergency services network portion 120 is functional for routingcalls and service request between the mobile network portion 110 and thePSAP 130 via an emergency services message entity (ESME) that isconventionally functional for routing and processing the out-of-bandmessages related to emergency calls and an emergency services networkentity (ESNE) that is conventionally functional for routing andprocessing the voice band portion of the emergency call. The PSAP 130 isthe terminating end-point (i.e., operator) responsible for answering toemergency services calls and arranging the emergency services (e.g.,fire, police, ambulance).

As above-mentioned, the mobile network portion 110 includes aconventional mobile network and positioning equipment. Typically, themobile network includes several base station transceivers (BTS) 111 eachserving a discrete geographical area or cell (which may be divided intoseveral emergency zones) for communicating over a radio link with amobile station (MS) making an emergency call. The mobile network alsoincludes one or more mobile switching centers (MSC) 113 each associatedwith a select plurality of BTSs 111 (via appropriate hardware links).Thus, each MSC 113 is associated with a select plurality of cells. TheMSC 113 is functional for providing conventional call managementfunctions (i.e., setting up and tearing down connections for the call)and routing of emergency calls to the emergency services network portion120.

The network-based position equipment includes position determiningequipment (PDE) 117 devices functional for determining the geographicposition of the MS when the mobile station user initiates a call orwhile the user is engaged in a call. Each PDE 117 is associated with amobile position center (MPC) 115 that is functional for selecting theappropriate one or ones of a PDEs 117 to use for determining position.The MPC 115 is preferably a processor-based apparatus that uses storedcomputer programs to implement its functions in which aspects of thepresent invention can be implemented in computer programs.Alternatively, aspects of the present invention can be implemented withinterface circuits, combination logic and/or sequential logic.

Summarizing the network entity relationship of the three network nodes(i.e., MSC 113, MPC 115, PDE 117) of the mobile network portion 110,each MSC 113 is associated with a plurality of cells. Further, the MSC113 is assigned to only one MPC 115, but each MPC 115 may be associatedwith multiple MSCs 113. Additionally, each MPC 115 is associated withmultiple PDEs 117 and each PDE 117 can be associated with multiplecells. The combinations of MSCs and cells serviced by a particular MPC115 are contained in a database in the MPC 115 and in separate andindependent databases in the associated PDEs 117.

In conventional operation, a 911 emergency call from the MS is routed tothe MSC 113 which routes the 911 call to the emergency services networkportion 120 for further routing to the appropriate PSAP 130. Along withthe routed call, the MCS 113 includes identification of both the servingcell and MSC. The MCS 113 may also send this id information to itsassigned MPC 115. Subsequently, the PSAP 130 may request or query mobilepositioning information for the MS via the emergency services networkportion 120, which pulls the position information from the MPC 115. Therequest incorporates information identifying the serving cell and MSC113, and the MPC 115 correlates this information with that received fromthe MSC 113 for selecting which PDEs 117 to be used for determining theposition of the MS.

Referring to FIG. 2 there is shown a table for illustrating aconventional database arrangement for the MPC 115 and PDE 117. The firstcolumn represents a list of numerical values each representing a MSC andone of the cells serviced by that MSC. The MSCs and cells each havetheir own assigned identification numbers, known in the wirelessindustry as MSCID and CELLID, respectively. Thus, each numerical valuein the first column is correlated with a MSCID/CELLID combination. Inthis example, the value zero “0” represent the combination of MSC number2020 and cell number 24001. As can be seen, MSC number 2020 may haveseveral cell combinations.

The success of emergency caller location quires depends on the accuracyof MSC id and cell id information stored with the MPCs and PDEs. Forexample, if for any reason a PDE 117 does not recognize the MSCID/CELLIDcombination in a position request from a MPC 115, the precision of alocation estimate will be adversely affected if it can be generated atall.

Thus, to maintain proper functionality, databases should be synchronizedto contain the same id information. Synchronization is typically aprocess of inputting the MSCID and associated CELLID data manually intoeach database. To assure accuracy, synchronization should be performedwhenever a new cell is added and/or re-configured, for example. As apractical matter, though synchronization is most often performed for theMPCs, it is not always performed on every PDE following a cellmodification. This is due, in some part, to the fact that there are manymore PDEs in the network than are MPCs. In addition, data entry errorscan be made while updating network node databases.

In accordance with exemplary embodiments of the present invention,network node databases are proactively audited to provide propersynchronization of stored information. More specifically, databaseentries of the MPC 115 and PDE 117 are continuously compared in areal-time manner to determine if there are any discrepancies.Discrepancies can be noted in a daily log or other type of periodicreport. The auditing is provided via standard protocols, interfaceconnections and connection monitoring between the MPC 115 and PDE 117.

The J-STD-036 standard defines the protocols and messages used on thenetwork interfaces between the reference model 100 network entities. Theinterface between the MPC 115 and the PDE 117 is known as the E5interface. In practical deployment, the E5 interface is an InternetProtocol (IP) connection. However, one problem with IP connections isthat long periods of silence can cause connection loss. To ensureinterface stability, an application level heartbeat message is typicallyused between the MPC 115 and PDE 117 simply for monitoring theconnection. Thus, the MPC 115 exchanges heartbeat signals (HB) with thePDE 117 for determining that the IP connection is active (i.e.,functioning properly). When the MPC 115 or PDE 117 recognizes that theHB sequence has been interrupted, both nodes initiate interfacetermination and re-establishment procedures.

Referring now to FIG. 3, there is shown a flow diagram more particularlyillustrating the above-mentioned conventional HB communication scheme.The method is initiated with the beginning of the HB at step 302followed by the “MissedHB” counter (step 304). MissedHB is a countervariable that represents the number of consecutive occurrences of missedHBs (i.e., no return HB from the PDE 117). Subsequently, the MPC 115sends the HB (step 306) to the PDE 117 and awaits a corresponding HBresponse (step 308).

If a HB response is returned from the PDE 117 (step 308), the MissedHBcount is set to zero and control is passed to the entry point (step 318)in anticipation of the next HB signal. If no HB response is returnedfrom the PDE 117, the MissedHB count in incremented by one (step 310)and the new count is compared to the “MaxMissedHB” (step 312).MaxMissedHB is a parameter that is set to the highest acceptable numberof consecutive missed HBs. If the MaxMissedHB count is exceeded, theappropriate system nodes initiate Interface termination andre-establishment procedures step (314) and the MissedHB is set back tozero (step 316) and control is passed to the entry point (step 318) ofthe flow diagram for preparation of the next HB signal. If theMaxMissedHB is not exceeded, control is passed to the entry point (step318).

In accordance with a preferred embodiment of the present invention,database auditing is enabled by enhancing the above-mentionedconventional HB scheme. More specifically, functionality is enhanced byincluding database entries or files in a GPOSREQ(HB) signal between theMPC 115 and PDE 117. In other words, in accordance with the J-STD-036standard, a HB signal is implemented by means of a pre-defined timed geoposition request (GPOSREQ) signal from the MPC 115 to the PDE 117 withthe request type (REQTYPE) parameter set to HB (i.e., Heartbeat) andfurther including a database file from the MPC 115 with the HB signal.The MPC 115 cycles through its database files (i.e., MSCID/CELLIDcombinations) including one entry in each HB signal sent to the PDE 117,each successive HB signal containing a different database entry. If theenhanced HB signal creates some type of error in the PDE'sfunctionality, the PDE 117 returns an error indication in the HB signal.From an error indication, it can be assumed that the MPC database filewas not recognized by the PDE 117. In the alternative, the geo positiondirective from the PDE 117 can be used to check database entries. Here,database files from the PDE 117 are included with the HB signal. The PDE117 cycles through its database files including one entry in each HBsignal sent to the MPC 115, each successive HB signal containing adifferent database entry. If this enhanced HB signal creates some typeof error in the MPC's functionality, the MPC 115 returns an errorindication in the HB signal. From an error indication, it can be assumedthat the PDE database file was not recognized by the MPC 115.

Referring to FIG. 4 there is shown a flow diagram illustrating theinventive audit method. Following initiation of the HB (step 302), theMissedHB counter is set to zero and the MSCID/CELLID value from the MPC115 database is set to zero (step 404). Subsequently, the MPC 115 sendsthe GPOSREQ(HB) with the current MSCID/CELLID value to the PDE 117 (step406) and awaits the PDE's response (step 308).

If no response is received, the control passes to steps 310, 312, 314,316 and 318 as described and shown in FIG. 3. However, if a response isreceived, the HB is set to zero (step 320) and a determination is madeas to whether the response is “normal” (i.e., does it indicate anyerrors) (step 422). If a determination is made that the response isnormal, the MPC 115 assumes the database entries match properly (step424) and the MCEID/CELLID value is incremented to the next combination(step 426). Control is then passed to the entry point (step 318) inanticipation of the next HB.

If a determination is made that the response indicates an error, it isan indication that the PDE 117 database does not contain the currentMSCID/CELLID value (step 428). Subsequently, the MPC 115 includes thisentry in a problem log (step 430). The problem log can be an ASCII textbased log file, for example, that the MPC 115 generates. The problem logcontains unrecognized MSCID/CELLIDs and is deliverable to the systemoperator for review and/or correction. Following step 430, control ispassed again to step 426 for incrementing the MSCID/CELLID value to thenext combination. In a preferred embodiment, the above-describedauditing method is embodied on computer-readable medium associated withthe MPC 115.

Of course, it should be understood that the order of the steps and/oracts of the step or algorithms discussed herein may be accomplished indifferent order depending on the preferences of those skilled in theart. Furthermore, though the invention has been described with respectto a specific preferred embodiment, many variations and modificationswill become apparent to those skilled in the art upon reading thepresent application.

1. A system for auditing node databases in a wireless telecommunicationnetwork, the system comprising: a central node on the wirelesstelecommunication network the central node including a first memory, afirst processor, and a first database stored on the first memory; afirst database in communication with the central node; a local node onthe wireless telecommunication network having a communication link withthe central node; the local node including a second memory, a secondprocessor a second database in communication with the local node; afirst logic stored on the central node, the first logic enabling thecentral node to initiate a monitoring signal to monitor thecommunication link between the central node and the local node forreestablishing the communication link therebetween, the monitoringsignal being a periodic heartbeat signal which includes an initialsignal from the central node to the local node and a correspondingreturn signal from the local node to the central node, whereininformation indicative of a first database file is incrementallyincluded with a sequential heartbeat signal such that each heartbeatincludes information representing a different file; a second logicstored on the local node, the second logic enabling the local node todetermine that the first database file included with the heartbeat doesnot match a second database file, and to generate an error, the errorbeing included in the return signal; and a third logic on the wirelesstelecommunication network for generating a report relating to the firstdatabase file that does not match the second database file.
 2. Thesystem of claim 1, wherein the third logic further enables the firstprocessor to terminate and re-establish the communication linktherebetween.
 3. The system of claim 1, further comprising: a MobileSwitching Center (MSC) in communication with the central node; and aBase Transceiver Station (BTS) in communication with the MSC, whereinthe MSC and the BTS each have a unique identification number, whereinthe BTS provides telecommunication service to a Mobile Subscriber (MS)within a known discrete geographical area, and wherein the uniqueidentification numbers for the MSC and the BTS are stored in the firstdatabase file.
 4. The system of claim 3, further comprising apositioning logic on the central node for selecting a correspondinglocal node in order to determine the discrete geographical area fromwhich the MS initiates an emergency call, the selecting being based onthe information in the first database file.
 5. The system of claim 1,further comprising: an Emergency Services Network Entity (ESNE) forrouting and processing a voice band portion of the emergency call; andan Emergency Services Messaging Entity (ESME) for routing and processingan out-of-band message related to the emergency call.
 6. The system ofclaim 5, further comprising a Public Safety Answering Point (PSAP) foranswering the emergency call and for arranging an emergency service inresponse to the emergency call.
 7. The system of claim 1, wherein themonitoring signal is a GPOSREQ(HB) signal.
 8. A system for auditing nodedatabases in a wireless telecommunication network, the systemcomprising: a central node on the wireless telecommunication network,the central node including a first memory, a first processor, and afirst database stored on the first memory, the first database includinga first plurality of files; a local node on the wirelesstelecommunication network having a communication link with the centralnode, the local node including a second memory, a second processor, anda second database stored on the second memory, the second databaseincluding a second plurality of files; a first logic stored on the firstmemory, the first logic enabling the first processor to initiate amonitoring signal to monitor the communication link between the centralnode and the local node for reestablishing the communication linktherebetween, the monitoring signal being a periodic heartbeat signalwhich includes an initial signal from the central node to the localnode; a second logic stored on the second memory, the second logicenabling the second processor to generate a corresponding return signalfrom the local node to the central node, wherein information indicativeof the second plurality of files is incrementally included with asequential return heartbeat signal; and a third logic on the centralnode to determine that the second plurality of files included with thereturn heartbeat does not match the first plurality of files, and togenerate an error, the error being used to generate a report.
 9. Thesystem of claim 8, wherein the third logic further enables the firstprocessor to terminate and re-establish the communication linktherebetween.
 10. The system of claim 8, further comprising: a MobileSwitching Center (MSC) in communication with the central node; and aBase Transceiver Station (BTS) in communication with the MSC, whereinthe MSC and the BTS each have a unique identification number, whereinthe BTS provides telecommunications service to a Mobile Subscriber (MS)in a known discrete geographical area, and wherein the uniqueidentification numbers for the MSC and the BTS are stored in the firstdatabase file.
 11. The system of claim 10, further comprising apositioning logic on the central node for selecting a correspondinglocal node in order to determine the discrete geographical area fromwhich the MS initiates an emergency call, the selecting being based onthe information in the first database file.
 12. The system of claim 8,further comprising an Emergency Services Network Entity (ESNE) forrouting and processing a voice band portion of the emergency call; andan Emergency Services Messaging Entity (ESME) for routing and processingan out-of-band message related to the emergency call.
 13. The system ofclaim 12, further comprising a Public Safety Answering Point (PSAP) foranswering the emergency call and for arranging an emergency service inresponse to the emergency call.
 14. The system of claim 8, wherein themonitoring signal is a GPOSREQ(HB) signal.